:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary: #38bdf8;
    --light: #f8fafc;
    --dark: #0f172a;
    --gray: #64748b;
    --success: #10b981;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f1f5f9;
    color: var(--dark);
    line-height: 1.6;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 导航栏样式 */
header {
    background-color: white;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo img {
    height: 40px;
}

.logo h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
}

.nav-links {
    display: flex;
    gap: 30px;
}

.nav-links a {
    text-decoration: none;
    color: var(--dark);
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: var(--primary);
}

.nav-links a.active {
    color: var(--primary);
}

.auth-buttons {
    display: flex;
    gap: 15px;
}

.btn {
    padding: 8px 20px;
    border-radius: 6px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
    border: none;
    text-decoration: none;
    display: inline-block;
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--primary);
    color: var(--primary);
}

.btn-outline:hover {
    background-color: var(--primary);
    color: white;
}

.btn-primary {
    background-color: var(--primary);
    color: white;
}

.btn-primary:hover {
    background-color: var(--primary-dark);
}

/* Hero区域 */
.hero {
    padding: 100px 0;
    background: linear-gradient(135deg, #e0f2fe 0%, #dbeafe 100%);
    position: relative;
    overflow: hidden;
}

.hero-content {
    display: flex;
    align-items: center;
    gap: 50px;
}

.hero-text {
    flex: 1;
    z-index: 2;
}

.hero-text h2 {
    font-size: 3rem;
    line-height: 1.2;
    margin-bottom: 20px;
    color: var(--dark);
}

.hero-text p {
    font-size: 1.2rem;
    color: var(--gray);
    margin-bottom: 30px;
    max-width: 90%;
}

.hero-image {
    flex: 1;
    position: relative;
}

.hero-image img {
    width: 100%;
    border-radius: 12px;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.hero-buttons {
    display: flex;
    gap: 20px;
    margin-top: 30px;
}

.btn-lg {
    padding: 12px 30px;
    font-size: 1.1rem;
}

/* 功能特点 */
.features {
    padding: 100px 0;
    background-color: white;
}

.section-title {
    text-align: center;
    margin-bottom: 60px;
}

.section-title h2 {
    font-size: 2.5rem;
    color: var(--dark);
    margin-bottom: 15px;
}

.section-title p {
    font-size: 1.1rem;
    color: var(--gray);
    max-width: 700px;
    margin: 0 auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
}

.feature-card {
    background-color: var(--light);
    border-radius: 12px;
    padding: 30px;
    text-align: center;
    transition: transform 0.3s, box-shadow 0.3s;
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    width: 70px;
    height: 70px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 25px;
    color: white;
    font-size: 1.8rem;
}

.feature-card h3 {
    font-size: 1.4rem;
    margin-bottom: 15px;
    color: var(--dark);
}

.feature-card p {
    color: var(--gray);
}

/* 演示区域 */
.demo {
    padding: 100px 0;
    background: linear-gradient(to bottom, #f0f9ff, #e0f2fe);
}

.demo-container {
    display: flex;
    align-items: center;
    gap: 50px;
}

.demo-content {
    flex: 1;
}

.demo-content h2 {
    font-size: 2.5rem;
    margin-bottom: 25px;
    color: var(--dark);
}

.demo-content p {
    font-size: 1.1rem;
    color: var(--gray);
    margin-bottom: 30px;
}

.demo-box {
    flex: 1;
    background-color: white;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.chat-container {
    height: 350px;
    overflow-y: auto;
    padding: 15px;
    border-radius: 8px;
    background-color: #f8fafc;
}

.chat-message {
    display: flex;
    margin-bottom: 20px;
}

.chat-message.user {
    justify-content: flex-end;
}

.avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 15px;
    flex-shrink: 0;
}

.user .avatar {
    background-color: var(--primary);
    color: white;
}

.ai .avatar {
    background-color: var(--success);
    color: white;
}

.message {
    max-width: 70%;
    padding: 12px 16px;
    border-radius: 18px;
}

.ai .message {
    background-color: white;
    border-top-left-radius: 5px;
}

.user .message {
    background-color: var(--primary);
    color: white;
    border-top-right-radius: 5px;
}

/* 使用场景 */
.use-cases {
    padding: 100px 0;
    background-color: white;
}

.cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.case-card {
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s;
}

.case-card:hover {
    transform: translateY(-5px);
}

.case-header {
    padding: 20px;
    background-color: var(--primary);
    color: white;
}

.case-body {
    padding: 20px;
    background-color: var(--light);
}

.case-body ul {
    padding-left: 20px;
}

.case-body li {
    margin-bottom: 10px;
}

/* 响应式设计 */
@media (max-width: 900px) {
    .hero-content, .demo-container {
        flex-direction: column;
    }

    .hero-text h2 {
        font-size: 2.2rem;
    }

    .section-title h2 {
        font-size: 2rem;
    }

    .nav-links {
        display: none;
    }
}